Cable layer conversion
A crucial aspect in realizing Offshore wind farms is the installation of subsea cables that transport the generated electricity to shore. Each offshore wind farm requires a unique cable design to realize safe transportation of the generated electricity. Next generation cable laying vessels are designed to conquer the unique challenges that emerge with the up-and-coming floating wind industry. One of these processes was guided by Saltwater.
Saltwater was contracted by Triasmitra to perform a feasibility check on a proposal to convert the PSV Skandi Sotra to a cable laying vessel. During the feasibility study the impact of modifying the Skandi Sotra to a cable laying vessel was investigated. The deliverables consisted of a new design matching client requirement.
During this process, multiple redesigns of the vessel’s deck layout were executed. The main goal was to achieve an optimized cable laying layout. The redesigned general arrangements considered: required deck space reservations, cable laying equipment and increasing the original accommodation to 56 berths.
Besides a new general arrangement, structural related items impacted by the conversion were investigated. Items such as required number of bulkheads, bow height, location of collision bulkhead, equipment number, required freeboard, bending moments and shear forces are all verified and are after conversion still in accordance with class and flag state, respectively.
In addition to above mentioned scope an investigation of the impact on stability due to the conversion was executed. A preliminary lightship weight and a new deadweight were conducted. The converted vessel has a carrying capacity of 1500 km of cable (repeater and repeaterless) for the SA type. A total of 13 loading conditions were evaluated and all were found sufficient which ensures stability of the vessel after conversion.
After delivering the results of our feasibility study, the client is now ready to investigate their options regarding different conversion solutions matching their budget. A process of requesting offers for the conversion by different shipbuilders will be the next phase.
Scope of work:
- General arrangement
- Reviewing delivered general arrangement
- Investigating different design solutions
- Updating/amended the general arrangement resulting in an improved layout
- Investigating impact of new design on relevant rules and regulations
- Cable carrying capacity
- Cable tank sizing
- Loading conditions